Portable drilling tools are well known in the prior art. Drilling tools are commonly used to drill holes in various surfaces, such as a wall, floor ceiling and the like. The drilling tool is required to be held at various inclinations to drill the hole at a desired angle. Mostly, the drilling tool is required to drill holes substantially horizontal to a ground surface. Leveling aids for small drilling tools are known, such as a built in water-level or a corresponding electronic version. For bigger drilling tools, especially core drilling tools, this does not work during drilling because of the strong vibrations. When a large number of holes are required to be drilled in a surface at a desired inclination, a mechanical level guide is utilized to start the drilling at a correct inclination. However, when the a big drilling tool is in operation, the drilling tool vibrates a lot. If a level aid is mounted on a drilling tool with strong vibrations, the vibrations cause the level aid to vibrate as well, causing problems in its functioning and may be visibility. This can lead to drilling of holes by the drilling tool at an incorrect inclination.
In light of the foregoing, there is a need for a level aid for a drilling tool whose working is substantially unaffected by vibrations of the drilling tool in operation.